Last Updated on 08/17/2025 by Melissa Henning
What if every student had a chance to be right—and to explain why? That’s the magic behind Which One Doesn’t Belong? (WODB), a dynamic visual routine designed to promote mathematical thinking and reasoning. It invites learners to explore patterns, justify reasoning, and celebrate diverse perspectives. Whether you’re teaching kindergarteners or high schoolers, this tool transforms classroom discussions by shifting the focus from finding the “correct” answer to uncovering multiple valid ones.
Each visual prompt presents four objects arranged in a 2×2 grid, carefully selected so that any one of them could be considered the “odd one out”—depending on how you look at it. Categories range from Shapes and Numbers to Graphs, Expressions, Photos, and more, making it accessible across grade levels and subject areas. For example, imagine a red circle, a blue circle, a red square, and a blue triangle. One student might say the red square doesn’t belong because it’s the only shape that isn’t a circle. Another might argue the blue triangle is the outlier because it’s the only three-sided figure. Both perspectives are valid—and that’s the point. This routine encourages students to think critically, articulate their reasoning, and listen to others’ ideas, fostering a classroom culture where every voice is valued and matters.
Applying the Triple E Framework
The Triple E Framework, created by Dr. Liz Kolb, states that “effective technology integration begins with good instructional strategies and not fancy tools” (tripleeframework.com). Dr. Kolb wrote a book, Learning First, Technology Second (ISTE, 2017), which discusses the Triple E Framework and lays out the three main uses of technology in education: to Engage, Enhance, or Extend learning goals. We can use this framework to decipher why we use specific classroom tools. It is essential that we understand why we are using technology, not just incorporating it as a time-filler, but rather as a partner in achieving our learning goals. Here is a rubric based on the Triple E Framework you can use to evaluate whether WODB (or any other technology) is a good fit for your learning goals and whether you should incorporate it into your lesson.
- Engage in learning goals: Which One Doesn’t Belong? motivates students to begin learning by thinking critically and explaining why their choice makes the most sense. There are no advertisements or sound effects to distract students’ focus from the activity and their own critical thinking as they explain their answer and why. In addition, WODB allows students to be active rather than passive learners when they answer why they chose the card. Students are actively engaged rather than just reading a text or listening to a lecture. WODB also offers various ways to differentiate for your students’ learning needs and levels. Success is redefined from “getting the right answer” to “thinking critically,” reducing anxiety, and building confidence in all levels of learners.
- Enhance learning goals: Which One Doesn’t Belong? aids students in developing, understanding, and explaining the content. Students deepen critical thinking by analyzing relationships, identifying patterns, and constructing logical arguments. Students must examine multiple attributes simultaneously and justify their reasoning. The use of technology allows students to find topics and collections more quickly. For example, groups of students can instantly find collections of images to use for the game. Students can also instantly pick a topic (Shapes, Numbers, Graphs, Expressions, Photos, Incomplete Sets, and Miscellaneous) and find numerous collections of 2×2 images to discuss. The topics can also help with both differentiation and scaffolding. For example, the first time students try the activity, they could start with something simpler, such as Photos. They could gradually move up to Numbers and then Incomplete Sets, as they learn the activity process.
- Extend learning goals: Dr. Kolb describes extended learning as an opportunity for students to learn, connect, and collaborate outside the regular school day and as a way to create a bridge between school learning and everyday life experiences. The ability to think critically and share reasoning is a life skill that all students must use in any future class or career. This resource would work well on virtual learning days for students to complete at home. Students could view one collection of visuals and take a screenshot. From there, they could add the screenshot to a class Padlet (reviewed here) and explain why they chose the image they felt did not belong. Another option would be for the teacher to put an image on Padlet and have students reply with their choice of what does not belong, allowing all students to use the same image. Either of these options could also be shared with another class for feedback, offering a collaboration activity between higher and lower grades.
If you are new to using the Triple E Framework, let’s discuss how to evaluate and assess student progress. One of the benefits of this resource is that every student can contribute meaningful insights, creating successful experiences that build self-efficacy. There’s no “wrong” answer when reasoning is sound. Hearing student participation and their reasoning is one way to evaluate whether the instructional goals were met. Teachers gain immediate insight into student thinking through verbal explanations, revealing misconceptions and areas for growth in real-time. Rather than testing memorized procedures, you can assess genuine mathematical reasoning, critical thinking, and communication skills that transfer to other contexts. This activity provides an excellent opportunity to practice the Thinking Routine, “What Makes You Say That.” As a great scaffold for students, this Thinking Routine asks students to really think deeply about their why and to evaluate their own thinking and reasoning. WODB offers a routine that truly encourages students to evaluate their own rationale and consider alternative perspectives, developing internal feedback systems.
SAMR Connection
The SAMR Model, by Dr. Ruben Puentedura, suggests that technology implementation has four levels. Therefore, we can use this model as a guideline to analyze how integrating technology into our instructional plans can create an instructional shift in our lessons. Before selecting classroom technology, continually evaluate your purpose: What specific learning goal will the activity using this tool address? How does it fit your student’s needs? WODB offers flexibility across all SAMR levels—from replacing traditional flashcard exercises to creating new learning experiences that were previously impossible. WODB could be used at the Substitution, Augmentation, Modification, and Redefinition levels of SAMR.
- Substitution: The substitution level is the most basic level of SAMR, referring to a situation where technology acts as a direct substitute without any functional improvements. WODB uses a digital game instead of traditional flashcard images. For example, a primary group of students could see four different shapes on a paper and have to explain which one doesn’t fit; the same activity could be done using technology. Using technology rather than physical cards allows the technology to replace paper cards, but the core thinking activity remains the same.
- Augmentation: At the level of augmentation, the technology acts as a direct substitute but also includes some functional improvements. The technology allows for instant differentiation. For example, younger students can use the Photos while older students can use the Incomplete Sets. And for the more advanced students, the open-ended nature prevents quick finishers from becoming disengaged – there’s always another perspective to explore. Students might also be able to explain their reasoning by recording audio responses with a tool such as ScreenPal (reviewed here) or typing explanations for why they chose a particular card using a blog creation tool such as Telegra.ph (reviewed here).
- Modification: The level of modification occurs when technology allows for significant task redesign. This level could be reached by having students create their own “Which One Doesn’t Belong?” card sets using digital tools, incorporating images, videos, or interactive elements. They might design themed sets (historical figures, scientific concepts, literary characters) and share them with classmates. The activity becomes more about critical thinking and justification of multiple correct answers rather than finding the single “right” answer. Canva Storyboard Templates (reviewed here) would work well for creating the cards, as they already have four frame templates.
- Redefinition: The highest level of SAMR, redefinition, occurs when technology allows for the creation of new tasks that were previously inconceivable. Students could collaborate globally with other classrooms to create and discuss culturally specific “Which One Doesn’t Belong?” challenges, exploring how different perspectives lead to different valid answers. If you want to connect with classes worldwide, try ePals (reviewed here). This game would be an ideal activity as an icebreaker as you start introducing new cross-cultural activities and meeting the classes that you may connect with, discussing topics, and getting to know one another. You may consider using Zoom (reviewed here) to communicate with the other classes for this activity.
Come back and join us for Part 2 of the Tech Tool of the Month: Which One Doesn’t Belong?, where we’ll discuss using the tool and classroom ideas. In the meantime, let us know how you have used WODB in your instructional setting in the comment section below.